Tonearm mount on the plinth or on Pillar ?

czarivey,

As I stated, some quakes are not felt, but they occur and are registered.  So I may possibly have been listening to vinyl sometime while one happened.

But you missed my point, unless you were just being humorous.  The danger would be for my arm position to be shifted during that event so it would be out of alignment the next time I did play a record.  

I'd prefer that relationship (platter/record to arm/stylus) to be locked in place.

And thanks for weighing in with logic Ralph.  

Other posts here include testimony by folks who utilize "naked" plinths (none at all, only support columns for the motor unit) with separate tonearm pillars.  They rave about their results.

I've not tried that but I remain skeptical.  Just consider how critical the accurate set up alignment is for the stylus, then ask yourself how that can be achieved when the cartridge/arm mounting is not "fixed" relative to the platter/record?

So I agree with moonglum.  Plus I live on the West Coast where we are subject to earthquakes, some of which go unfelt.  I don't want my tonearm "dancing" around somewhere close to the correct position.

I think I may need to offer a clarification on my reference to earthquakes. At least for those living with more stable terra firma who don't experience them.

My concern is not so much for movement while I'm listening (touche czarivey), although that is possible, but rather for shifting of the arm position whenever a quake occurs.  Since the table and arm (including bases) do not have the same mass their likelihood and degree of movement will not be the same.  And I may not even know the quake happened, and so to recheck alignment, but my system may not then sound "right" afterwards.

Of course as others mentioned there are other earth borne vibrations to be concerned with.  Is there a major highway nearby?  Any bus or large truck traffic?  Is there construction close to you?  And those are all external forces.  How stable is your turntable platform to begin with?

  

Chris, thanks for the update on your SP-10 Mk 2.  Your idea to mount your arm on a separate pillar and then bolt the pillar to the base (plinth), same as for the motor unit, is similar to the direction I've moved.  That is sort of a "middle ground" between a naked table and one that is directly connected. ;^)

My thinking is by not mounting the arm and motor unit to the same top layer of whatever material in the plinth but still have a fixed connection, any energy transfer between the two will need to travel a greater distance and (likely) through different materials, and thus be absorbed or at least diminished.  Now after multiple false starts I need to find someone local with the proper tools to build it for me.